EPISODE 40 [INTRODUCTION] [00:00:00] ANNOUNCER: Do you enjoy listening to On the Ear, but wish you could earn ASHA CEUs for it? Start today. SpeechTherapyPD.com has over 175 hours of audio courses on-demand, with an average of 19 new audio courses released each month. Here's the best part, each episode earns you ASHA Continuing Ed Credits. Oh, no wait. This is the best part. As a listener of On the Ear, you can receive $20 off an annual subscription when you use code Ear21. Just head to SpeechTherapyPD.com to sign up and use code Ear21, E-A-R-2-1 for $20 off your annual subscription. [00:00:48] DS: You're listening to On the Ear, an audiology podcast sponsored by SpeechTherapyPD.com. I'm your host, Dr. Dakota Sharp, AuD, CCC-A, audiologist, clinical professor, and lifelong learner. While I primarily work with pediatric cochlear implants and hearing aids. I am absolutely intrigued by the many areas of audiology and communication in general. This podcast aims to explore the science of hearing, balance, and communication with a variety of experts in hopes of equipping you to better serve your patients, colleagues, and students. Let's go. We are live and On The Ear, brought to you by SpeechTherapyPD.com. [INTERVIEW] [0:01:34] DS: Since the FDA approved cochlear implants as an intervention for single-sided deafness in 2019, our approach to evaluating candidates, programming the devices, and evaluating outcomes has continued to evolve. Now that we're coming up on four years since approval, it seemed like a good idea to look back on previous treatments for SSD, how a cochlear implant can help with this population, and what the future looks like for this intervention. Today's guest is here to explain all of that good stuff. Dr. Margaret Dillon, AuD Ph.D., is an associate professor and the director of clinical research and the director of the cochlear implant clinical research lab in the Department of Otolaryngology and Head and Neck Surgery at the University of North Carolina at Chapel Hill. She conducts clinical research investigating outcomes for new indications of cochlear implantation and the effectiveness of individualized mapping procedures on the performance of pediatric and adult cochlear implant and electric acoustic stimulation device users. Just a couple of financial disclosures, Dr. Dillon is supported by research grants provided to the University by MED-EL Corporation and the NIH National Institute on Deafness and Other Communication Disorders. I'm the host of On The Ear and received compensation from SpeechTherapyPD.com and Dr. Dillon received compensation for her contribution to today's presentation. I'm so excited to have you here, Meg, you are maybe one of my favorite colleagues, if that's fair to say, even though we don't even get to interact that much, every time I get to see you, it's such a joy. When you agreed to do this, it was the best news. Thank you for being here. [0:02:54] MD: I'm very excited. I think it's going to be a lot of fun. [0:02:56] DS: That is a really short bio for somebody who's done a lot of stuff in a short amount of time. I want to get into how you have your AuD and Ph.D. because I know that was a more recent development, right? Your Ph.D., at least. [0:03:08] MD: Yes. My story, the quick piece of how I got into audiology, as an undergrad, I had seven different majors, I think. I just really Ð [0:03:17] DS: Oh, my gosh. [0:03:17] MD: Could not decide, could not figure out, and all over the place. I wanted to be a pediatrician. I wanted to be a lawyer. I thought about history for a little while. I mean, just all over the place. My dad was like, ÒYou really need to figure this out.Ó He was an elementary school principal. I went and observed one of his speech-language pathologists. I thought that was super fun and loved the experience working with children. I thought that's what I want to do. I want to be a speech-language pathologist. Part of the coursework as an undergrad includes an intro to audiology course. I'll never forget Dr. Rauch for that first day. He said, ÒHow many of you want to be audiologists?Ó I arrogantly didn't raise my hand, because I knew I wanted to be a speech pathologist. He said, ÒI'm sure at the end of this, I'm going to convert at least five of you.Ó It was a class, maybe like 50, 60 students. I loved it. I was hooked. I read everything. I read the supplemental materials. I was searching for other things. At the end of the semester, I went up to him and I said, ÒI want to be an audiologist.Ó He said, ÒI know.Ó Thankfully, I got into the University of North Carolina, AuD program. I had the unbelievable fortune of meeting Charles Finley, who was the engineer, mastermind behind the continuous interleaved signal coding strategy, which all cochlear implant manufacturers have today, some version of that. I loved implants. I wanted only to do implants. I asked Dr. Rauch, ÒCan I skip the hearing aid course and just do cochlear implants?Ó He said, ÒAbsolutely, not.Ó it was the best. I knew that's what I wanted to do. I did my fourth year specializing in adult cochlear implants, loved working with Marcia Clark Adunka. Then UNC hired me on to run some research projects with the otolaryngology team that was in collaboration with the UNC Health audiology team. It was amazing. I started to realize research was where I needed to be. I had my own questions. I didn't just want to answer other people's questions, but I didn't really know how to develop protocols well. I didn't have the statistical background. About seven years ago, I started doing the Ph.D. while also continuing to work full-time. It was challenging, but it was the greatest experience because I got some opportunities to work with the Anita Chatterjee and Jill [First 0:05:43]. Just really amazing people in the field that helped me expand my knowledge and think more creatively about ways to answer some of these clinical questions that we encounter all the time. Then graduated last year, and it's been amazing. [0:05:58] DS: Woo-hoo. [0:05:59] MD: Yeah. [0:06:00] DS: That's awesome. [0:06:00] MD: Yeah. [0:06:01] DS: I was one of those students myself where you're in the beginnings of your AuD program and either the program you're at or you've heard of ones that offered like an AuD Ph.D. and you're like, ÒYeah, you know, maybe. I might consider something like that.Ó Then you get started in your clinical work and maybe a little bit of research as a capstone project or something like that, and you're like, ÒOkay, maybe not. Maybe I'll stick to my AuD. I'll let those crazy people go after their Ph.D.s.Ó I think hearing stories like that is really inspiring to students out there who have considered it. I do think it takes a special person who's that passionate, who is that dedicated to learning new things and being a lifelong learner. I think you raise a good point too of having your own questions. There are a lot of people out there who do and they just don't know where to get started. I think considering a program like this could maybe be a good foundation to that idea. [0:06:46] MD: Yeah. I think thatÕs what so fun about our team is our clinical research labs are located within the clinic. It's this natural collaboration with the audiologist and with the physicians to talk about things that we're encountering, those challenging cases that we see, and then how can we approach that in a methodical way to help these patients hear better. I think it fuels a lot of excitement and energy that also is helping us provide better improving evidence-based practice for the way that we're treating these children and adults who have cochlear implants. it's amazing. I feel super spoiled with this position. [0:07:23] DS: It is awesome. This team is so cool. Okay. But we can't just sit and dwell on how amazing our team is, even though I would love to do that, too. [0:07:29] MD: Yeah. [0:07:30] DS: Now a lot of your focus, I guess lately, how a lot of it has been more on these place-based maps and involving imaging and things like that into cochlear implant mapping. Also in the bigger picture of things, I know you've done a lot of work with single-sided deafness, and I'm curious what led to some of your focus being Ð it sounded like you were already really passionate about cochlear implants, but maybe these more specific aspects of cochlear implant care. [0:07:52] MD: Yeah. One of the interests that we had was new indications for cochlear implantation. When I started working, it was bilateral, severe, profound, sensorineural hearing loss. We were investigating patients that had normal to moderate low-frequency hearing. There was that big question of, can you preserve hearing in patients when you're putting in a cochlear implant? Will they have functional acoustic hearing post-operatively that you could then fit them with the combination of acoustic and electric stimulation? It seemed like the most wild idea, can they fuse these two different signals in the same ear to have benefit? It was really fun working on that project and seeing one, that you could save hearing and a lot of hearing. Then two, that patients were able to combine the acoustic low-frequency information with the mid to high-frequency electric information and have this huge jump in speech recognition and quality of life. That started this area of research and thinking, who else could benefit, right? Now that we're seeing that you can combine acoustic with electric stimulation and you're not having this interference effect happening. I have to be honest. I remember in 2014, sitting in a conference hall hearing, Paul Van De Heyning from Belgium talk about single-side deafness and using a cochlear implant. I thought, whoa, we have gone too far, right? Like, IÕm actually, new to that. I think it was even earlier than that, and it must have been like 2012 because 2014 is when we started our clinical trial here, but it was amazing to think about someone with normal hearing in one ear and then severe to profound hearing loss in the other ear and your options were pretty limited in treatments of what you could do to try to improve your hearing. To hear him talk about the benefits that they were seeing, it was just fascinating. That's what led us down this journey of maybe we should also think about it, but approach it in a very methodical way to see where are these benefits are coming from. [0:09:55] DS: Awesome. If you wouldn't mind, and one of our early Ð I mean, I think, the fourth or fifth episode of the podcast was with Lisa, Dr. Lisa Park, and we were talking about pediatric SSD. I mean, I think this was like not too long after that had been approved. This must have been like October 2020 or something. [0:10:13] MD: 2019, yeah. Oh, okay. [0:10:13] DS: It was like the next year. It was very, very, very new at the time. If you wouldn't mind giving us a quick refresher on what impacts we see for SSD and then why we think a cochlear implant would be a good option for someone with single-sided deafness. [0:10:26] MD: Yeah. For adults and for kids too, really the effects that we're seeing in these patients is they're reporting poor sound source localization to the ability to identify where sounds are in your auditory space and poor speech recognition and noise. You're at a party and you've got two people talking to you and it's really hard to follow who is speaking at which time above all the chatter that's happening in the background. These patients are also reporting poor quality of life and increased hearing handicap as compared to their normal hearing peers. For kids, it's even more interesting, because you see Ð we used to think one good ear was enough, one normal hearing ear was enough, but there's evidence of poor language outcomes. Again, the difficulty understanding speech and noise and localization, but they also are reporting these higher levels of fatigue and difficulty in education. I think it's about one-third of children with unilateral hearing loss have to repeat a grade and poor performance on cognitive measure. Clearly, there's something about only having input to one ear that is, it's not enough, right? That's what led us to think more critically about what options could there be for this patient population. Because at the time, your only option was to wear a bone-conduction device or a cross-hearing aid. We're placing a microphone on that poor-hearing ear, picking up that signal, and routing it over to the better-hearing ear. Everything's going up one auditory pathway. That's not helping us restore any binaural hearing cues. It's giving us access to sound, but it's not providing that binaural information that can help with localization and speech recognition, and noise. [0:12:07] DS: That makes sense. When we first started seeing the first few patients who were, I guess, in these early research studies who were receiving cochlear implants, what kind of things did we see early on, both as benefits and then also limitations for the device? [0:12:23] MD: I think this piece is just fascinating. To take a step back, when we designed our clinical trial for the adults first, one thing that we have for the inclusion criteria was the Tinnitus Handicap Inventory, which ranks the severity of the tinnitus. It had to be moderate or less because something that you see with patients with simplified deafness is there is this high incidence of severe catastrophic tinnitus. We wanted the patients that were proceeding with the cochlear implant to have the aim of restoring binaural hearing abilities and not a resolution of the tinnitus or suppression of the tinnitus, because we have seen with cochlear implants that the majority of patients will have some tinnitus suppression, but there are some patients that have no suppression of their tinnitus or in some cases, it's gotten worse. We really wanted the focus to be on binaural hearing and improving localization speech recognition and noise. That was one of the [ÔcanÕt seeÕ 00:13:21] criteria. The other thing which I like to point out, and it's a bit of verbiage or a bit of semantics, but the currently approved indications are for severe to profound hearing loss. What we were going for were for patients that qualified for cochlear implants in one ear. We established it as moderate to profound hearing loss with a CNC word score of 60% or less in that affected ear. I like to use a term unilateral hearing loss because clearly there is some hearing in that ear. What we saw in this first group of adults, and I set the bar low when I was counseling them. I said, ÒYou know, you may not hear anything. You may hear something and it's the worst thing you've ever heard and it never gets better. You may hear something and maybe we'll hear a little bit of words.Ó There was no one where I said, you're going to knock it out of the park on day one, because we really thought, how is it that you could take this really crude signal from a cochlear implant and combine that with a normal hearing ear. One thing with our study is we selected the long electrode array, the 31.5-millimeter lateral wall array from MED-EL for the trial because in a previous study, we had randomized conventional cochlear implant patients to get either that 31, that long electrode array, or a shorter electrode array and follow them over the course of the year. What we saw was that patients that had that longer array did better faster than those that had the shorter electrode array. When we were designing the single-side deafness study and we were thinking about restoration of binaural hearing, we thought, letÕs implant the long electrode array, because we may be better approximating those default filters with the normal tonotopic organization of the cochlea, so that we have a match with the normal hearing ear. All of the adults received the 31.5-millimeter array and add a month, the first few came in and I asked them we had activation and then we followed them at one month, three months, six months, nine months, and 12 months. At the one month, that first interval that they returned. The first few were saying to me, ÒOh, Meg, it sounds like my normal hearing ear. When I put it on for a second, it will sound robotic, but then it fuses with my normal hearing ear. I can't really tell which sound is the cochlear implant, which sound is the normal side.Ó [0:15:46] DS: Wow. [0:15:46] MD: I thought, well, I think they're just being nice, right? Like, they're just Ð they know IÕve put a lot into the studies, so they want to make me feel good. But we saw that on CNC word recognitions when we were testing implant alone, the trajectories of the improvement in speech recognition was very similar to what we would see with conventional cochlear implant patients. We saw these huge improvements in localization right out the gate. That was very exciting. We also saw the study improvement for speech recognition and spatially separated noise, as well. What we were seeing in the sound field was mirroring what they were saying to us. We also had them fill out the SSQ, the Speech Spatial, and Qualities of hearing questionnaire. They were also reporting significant improvements in the quality of sound on that questionnaire. It was just the most baffling thing. I will say, one of the things that we did early on, I'm so glad that we did, was on activation day, I would activate them or English King, who is the clinical audiologist at the time working with us would activate them. We'd send them over to the CCIC to work with one of the speech-language pathologists at Children's Cochlear and Plant Center at UNC. [0:16:59] DS: Shout out. Best team of all time. [0:17:02] MD: Just got to drop it in there. But they would see one of the speech-language pathologists there, an hour after activation and complete oral rehabilitation. Then we'd also have them do that at the one-month interval, as well. Then the speech-language pathologists would either continue to work with them, it was up to the patient's discretion, or they would do some recommended home activities as well. I think having one, the long electrode array, then two, the early use of oral rehab as part of the plan really benefited those patients and contributed to those early performance benefits that we were seeing, and that they were reporting. [0:17:41] DS: Yeah. You're starting to get a better picture of what rehabilitation looks like for a really successful patient. [0:17:45] MD: Yes. Yes. [0:17:47] DS: Yeah. In those early days, was there anything Ð I mean, it sounds like, a lot of this could have been a bit surprising, especially how quickly people were acclimating. That's my question is what was surprising? I guess that could probably be the biggest one, right? But is there anything else that really stands out to you as something you weren't expecting or that you were learning from this group early on? [0:18:04] MD: We did some pitch studies, pitch perception studies with them and saw that early on that they were perceiving the pitch of the center frequency that we were sending to a given electrode contact that it was within that range. That got us thinking about the importance of place of stimulation and trying to match cochlear tonotopicity. I have to say, and it still shocks me now is when patients say, they like it because you listen to these simulations of cochlear implants and you think, why would anyone want to listen to that all day combined with their normal hearing? Really, the reason we set up the protocol the way that we did where we would run the tests with the cochlear implant on and off at every interval was to see if the implant was causing an interference effect. Was it in any of these conditions when you had the implant on that it was so distracting that your performance actually went down as compared to when the implant was off and you just had your normal hearing ear? We didn't see any evidence of that, which still is just amazing if you think about the way the brain is able to fuse those two very different signals. I have to say that was the most surprising. After we saw the performance benefit in the adults, that's when we got a little bit more confident and decided that we would do the same study in children and seeing them light up has got to be one of the highlights of my career is seeing these kids just do amazing things in the sound field that also be so engaged and excited about their implant. It's been a fun journey. [0:19:37] DS: That's great. I'm curious too, since those early days, has the timeline for anything changed in terms of what you expect? I guess maybe how you counsel the timeline of skill acquisition or localization or things like that? Because I know you were saying early on, your counseling was very, realistic might not be the right word. Guarded, maybe guarded, right? [0:19:57] MD: Yeah. Guarded is a great word. Yeah. [0:19:59] DS: Has that changed how you approach those conversations? Are they basically the same? How has that changed for you? [0:20:04] MD: I say that we still should counsel that way. I think our team does, even though we're very enthusiastic about this. I think being realistic and you need to put the work in. That's something to think about when you interpret data from clinical trial participants. These are people that were saying, ÒI have no other option. I am looking for something to improve my hearing. I'm so frustrated. I need something else. I've tried everything that's out there.Ó So they came looking for us. We actually reached maximum enrollment in our study in the adults for 20 within nine months, which was just unheard of for us. [0:20:41] DS: Wow. Yeah. [0:20:42] MD: It's not because we were actively looking for folks. It's because they were looking for us. They were looking for a solution. These were people that were willing to put in the work, wearing it multiple hours a day, doing their oral rehab consistently. I think this was a best-case scenario of if you have tried the other options and are unsatisfied that this is an option if you're willing to put the work in. One of my favorite stories from this patient cohort. There was one participant who did not believe me when I said you needed to wear it eight hours a day. When she came in her first time at the one-month interval, she was wearing it about four hours a day. At this point, we had seen a number of patients and all of them were having these significant improvements in localization. Hers was about the same. It was a little bit better than what it was pre-operatively, but it was about the same. She said, ÒI think I'm doing fine.Ó I said, well Ð and I showed her the plot. I said, ÒHere's everybody else way down here, having this huge improvement in localization. then here's you.Ó There's something about the human competitive spirit, so she was like, ÒOkay, all right, well, we'll see.Ó I don't think she fully believed me then. She started wearing it six hours. She came back at three months and she was like, ÒOkay, where am I now?Ó She had reached like the top of the box plot, right? Like she was getting into the area, but not there. I think that is where it triggered her. The next time she came in, she was 12 hours a day. She was one of the best at that point. I think counseling is very, very important because we're still learning what variables contribute to the success of that patient population. As you mentioned earlier, we're now doing things with imaging and mapping, and individualizing the settings based on where the cochlear implant is within a specific patient. I think that has a lot to do with it. I think the way that we program the devices we're selecting, how we counsel, are they doing oral rehab, all of that is contributing to the big outcomes that we're seeing in these patients. [0:22:42] DS: That's awesome. With all of this improvement in outcomes and just improved knowledge on how to approach this patient population, I feel like one of the biggest barriers to getting to that step can be insurance approval. Until the FDA approval in 2019, that really wasn't happening for most people without being in a study or that thing. I know you're more on the research side of things, but have you seen how insurances are approving this? Is that mentality changing? Is it becoming more accessible for people? [0:23:11] MD: It is becoming more accessible. I'd say there's still work that has to be done. There are some insurance companies that have been supportive of it. Then there are others where it takes a couple of rounds of submitting evidence that this is an effective treatment option and it is an FDA-approved indication for cochlear implants to get it through. Then I'm also frustrated that Medicare isn't supportive of it right now. Medicare is still the moderate to profound in both ears, the hearing loss in both ears, because in our sample, we saw that some of our older adults who were either in the single-side deafness or in the asymmetric hearing loss, which makes sense, right? You're going to have a little bit more hearing loss in that contralateral ear, the older you get. They were also having significant improvements. It speaks to that age is not a contraindication. The fact that this isn't on the table for Medicare beneficiaries, I think is frustrating. [0:24:06] DS: Absolutely. I mean, and it is good that things have improved a bit for private insurances. Yeah, with Medicare holding things back, that's a huge population who just doesn't have access to something that is proven really, really effective and very helpful. [0:24:18] MD: Yeah. Can increase independence and quality of life. It could have all these other benefits, not just what we're seeing in the sound field. Hopefully, Medicare will change its standing on that too. [0:24:29] DS: Yeah. Speaking of the sound field, actually, I'm curious when it comes to evaluating patients both pre and post-operatively. How has that evolved since you all first were formulating these studies seeking FDA approval? Are the things you emphasized and testing back then different than what you emphasize now? I know just peeking in and reading studies that have been related to some of the SSD research. There are some really cool localization tasks that are done, but I don't know too many people clinically who have access to some of that equipment. [0:24:57] MD: Yeah. Yeah. [0:24:58] DS: It's really cool equipment, but I don't know if everybody has it. What things are you seeing there just in terms of how that's evolved, I guess, both in determining a candidate and then also in monitoring their outcome? [0:25:09] MD: Yeah. Not many people have the massive sound booth that's needed to have a 180-degree arc of speakers, right? Like that's not something that's encountered clinically a lot. When we design the study, we are fortunate that we have the space where we can do these very specific spatial hearing setups to test this and to do localization assessments. We did have some conversations with our clinical team of how we can start to implement these things in the clinical population that also is not going to take two to three hours of testing that is more feasible when you're seeing these patients. One of the first things you think about with single-side deafness or moderate to found unilateral hearing loss is needing to isolate the input to the affected ear. For adults, they can tolerate masking being presented to that normal hearing ear. We did do a comparison study looking at whether you did a direct connect setup or if you had masking delivered to that ear, if you saw a difference in CNC word scores, and we did not. We didn't think we were having central masking effects when we were testing patients in the sound field, but there are the direct connect setups too, that are appropriate for testing word recognition and those are obviously a great idea for children because masking is definitely going to be distracting for them. I keep saying word recognition for a reason because I firmly believe that just based off of what we have right now and the evidence that we have now, that when we're assessing CNC criteria for cochlear implants, you're thinking about the audiometric profile, the hearing levels, so is that, well, CNC criteria is severe profound, but for us with the study, it was moderate to found sensory neural hearing loss, but what is speech recognition? You get your CNC word score, but I don't think there's really a need to assess sentences and quiet sentences and noise after that, because the reason that patient is coming in and seeking a cochlear implant is not because they're saying, ÒGosh, I really wish my word recognition and speech understanding in my poor hearing ears better.Ó It's because they want to use their two ears together. I think the time spent needs to be on binaural hearing measures. That's what our clinical team does is they'll measure unaided thresholds in both ears. They'll measure speech recognition with CNC words in both ears. Then the time is spent with the two-speaker set up assessing speech recognition and spatially separated noise. In most clinical booths, you have at least two speakers that are either 45 degrees separated or 90 degrees separated. If you turn your chair and you have the patient facing one speaker and the other speaker is directed towards the normal hearing ear, then you can test that condition within, without technology on the contralateral ear. Then you just turn the chair so that they're facing the alternative speaker. Now the masker can be delivered to the contralateral ear. It can be accomplished with our clinical setups, where you can test binaural summation, so having a speech and then masker from the same speaker testing device on versus off testing binaural squelch, where you have the masker delivered towards the poor hearing ear. Then the head shadow effect where you have the masker delivered towards the normal hearing ear. You can test all three of those conditions pretty quickly, clinically, with the traditional setup of 45 versus 90 degrees. I will caution, though that if you have multiple sound booths and some are 45 degrees apart and some are 90 degrees apart, that you want to make sure that you're always testing the patient in the same booth because we conducted a study where we'd look to see how much of a benefit do you get when you move that masker 90 degrees away versus 45 degrees away. There was a significant difference. Patients had better hearing when the masker was moved 90 degrees versus 45 because you have greater spatial separation. It's important to just keep that in mind that that little bit of a shift can have a big impact on outcomes or what you're measuring. [0:29:19] DS: That's really good advice. Yeah, I definitely want to keep that in mind. Wow, you just did a lot better this visit or no, you did a lot worse. What happened? [0:29:26] MD: Yeah. ItÕs just a setup. Yeah. [0:29:28] DS: Another thing, just a tip from working in pediatrics with this population, you want to watch them. You don't want to just be looking down at your scoring sheet, because they'll start leaning forward or leaning back. ThereÕs a twist into the side. Then na-na-na-na. I got to have this lined up just right. You got to keep an eye on them too, because they'll be a little sneaky when they're doing that test. [0:29:48] MD: Yeah. The interesting in these next couple of years, because there's been some fun experiments conducted with two speakers, where you can shift the levels between the two speakers and you can mimic a sound source that's in between those two. It could be that we have the ability to test localization as well in our clinical setups. Once we have that technology available. [0:30:12] DS: That's awesome. I love that this has become so much more approachable now, because early on just reading like, okay, they did this localization task. Okay, we got to figure out how to get this different setup. Now it's a lot more approachable for a lot of clinicians out there. I'm also curious when we talk about Ð whether it's quality of life or localization differences, I know the SSQ is a really popular questionnaire for single-sided deafness cases, especially when we're monitoring pre and post-implant outcomes. Are there any other questionnaires that you all like to utilize, so that you keep an eye on with these patients? [0:30:43] MD: Yeah. We use the tinnitus handicap inventory, as well, because we did want to monitor suppression of tinnitus in this patient population with the cochlear implant on. I kick myself that I wish that I had also administered it, asking them about when the cochlear implant was off because some of them did say that just the procedure itself caused a resolution of their tinnitus whereas others it was only when the implant was on. Then some of them reported over time as they wore their implant more and more that their tinnitus when the implant off became less and less or it took longer for it to ramp back up in the evening. I wish that had tracked that. Learn from my mistake on that. We have also started to use the CIQOL 35 from MUSC. We haven't been able to look at those results yet, but in our newer participants that have single-sided deafness, we've been administering that questionnaire so that we can look to see does it tell us something above and beyond what we were seeing with the SSQ. One of the things that I really like about the SSQ is that we all know that you can score it on the speech spatial and qualities of hearing subscales. Those three subscales. It's also been designed where you can analyze reports on these pragmatic subscales. Two of my favorites for the SSD population are pragmatic subscales under the qualities of hearing subscale. That's listening effort, which a lot of patients say that once they get their cochlear implant, it's easier to understand conversations, and that they don't feel as tired at the end of the day. That was one way for us to track that report, but also the quality of sound. That was a way where we could start to track how they were saying that it sounded more like normal hearing. Really that was just a beautiful side effect that happened from choosing the SSQ that I did not intend when we started the clinical trial, but it was really interesting to look at those data and see how that was developing and mirroring the patient report that we would not have been able to capture otherwise. [0:32:53] DS: That is really, really cool and a very recent episode of the podcast was with Dr. Teddy McRackan. all about how they developed the CIQOL questionnaire. I love how worlds collide there. I'm excited to hear more research that comes out with some results from that one too. [0:33:07] MD: Yeah. It's going to be fun to look at that data. Yeah. [0:33:09] DS: Cool. That's really great information on evaluating pre-post implant. How about the mapping itself? Are you all approaching mapping single-sided deafness cochlear implant cases differently than you would, a more traditional profound hearing loss or bilateral hearing loss? Is it about the same? I know I really want to get into the more recent work y'all have been doing with place-based mapping. But just I guess, if you can think back historically when you were first seeing these patients, was there anything that was different about how you approached mapping? [0:33:38] MD: Yeah. English King and I had a long conversation about this because we had a few patients that had paid out of pocket before we started the clinical trial to get a cochlear implant. They were just so frustrated and it was worth the money to them to get an implant. What we found at activation was that they hated the sound quality. They kept saying, ÒTurn it down, turn it down, turn it down.Ó Your intuition then is all right, just drop the MCLs and then slowly over time they'd allow you to increase that. When I thought about that, we know that if the sound level is not an appropriate volume, the expected benefit may not be what's observed for those patients. English and I are both more on the aggressive side when it comes to mapping. We agreed that the point of getting the implant was to improve binaural hearing. Instead of allowing the MCLs be low and ease them into an appropriate sound level, we decided that we would push patients to listen to an at an appropriate level at activation. One of the ways that when we had a very strict mapping protocol that we came up with because we also wanted that to be consistent. if the two of us, we had both trained with Marcia Clark Adunka. We were similar in our mapping style, but we wanted to keep that piece of it consistent because I really felt that that was going to be important in the benefit that patients were getting with the device. The protocol we came up with was first to plug the contralateral ear and measure electric thresholds behaviorally. That activation, we estimated them that at the one month, and then after that, we would always measure the electric thresholds. Then we would make sure the MCL levels were at that loud, but comfortable level. We would conduct loudness balancing using the adaptive comparison method where you ranked the loudness on electrode six and mid-frequency electrode. You confirm that that's the most comfortable loudness level. Then you compare the loudness of seven to six. You make sure that you're adjusting seven to match six since that's perfect. Then you work up the array and then you come back to six and you work down the electrode array. We spent a lot of time making sure that the levels were balanced across the electrode contacts and at that most comfortable loudness level. Then we take the earplug out and ask them if it was balanced with the contralateral ear. The majority of them, in fact, probably all of them at activation would say, ÒOh, it's way too loud.Ó But that would make sense, because it's different, right? Like it speaks that whole distracting piece of this is what's new. You are paying more attention to that than you are your normal hearing ear. We would not turn it down. We would leave it there. We'd have a conversation with them. They'd say, ÒOkay, it's starting to sound a little bit more like my normal hearing ear, as far as level. They weren't sound quality. I don't think a lot of them believed us that that was an appropriate level. Then again, so fortuitous that we had them see the speech-language pathologists right after that because they would do this direct connect setup. That helped the patient track what's an appropriate loudness to understand speech with the implant alone. [0:36:57] DS: Oh, cool. Cool. [0:36:58] MD: I think that is just so perfect in such a great way to help someone write out the gate, understand what's an appropriate loudness level, so that was something we spent a lot of time doing with the clinical trial. More recently, we've been doing ESRTs or measuring ESRTs in these patients as they're coming back for their annual visits. I wonder if we had it right at activation, and we should have left it there over the course of time because those levels would increase a little at the one month, increase a little at the three months and over the study period. When we measure their ESRTs for the majority of these folks that are coming back, the ESRT level is lower than where we had the behavioral level. We're seeing significant improvements on some of our spatial hearing measures, even acutely after changing it. Most of them say the ESRT level sounds too soft, but then they see the performance benefit they're having in the sound field and they're like, ÒOkay, great. Well, keep going with that.Ó Some of them like it right out the gate. I still think there's a lot to be learned about the best way to program this patient population. [0:38:06] DS: Yeah. We're not that far in yet, right? There's definitely a lot of room to learn more about that. I think that's awesome. I do see the struggle there of trying to figure out for this person who's never listened this way before, who has an ear that it's going to always be compared to every second of every day like what is loud enough or what is equal. I just can imagine that would be a real struggle, especially in those early stages. [0:38:31] MD: Absolutely. Yeah. [0:38:32] DS: What have you seen in terms of wear time in this population? I know like historically, in my own experience, this can be a tricky population to really get that buy-in. I mean, I guess I work with kids, right? Who maybe didn't have Ð they were pretty young when this whole processor didn't have as much buy-in in the process, maybe even literally out of their own wallet as much buy-in. Some of these adults really want it to work, right? What have been the struggles there and how have you navigated those? [0:38:58] MD: With the clinical trial participants, I told you about the one who needed a little convincing that you needed to wear it over eight hours. [0:39:05] DS: The competition, I guess, helps. Yeah. [0:39:07] MD: Yeah. It worked pretty well. All the rest of them were wearing it eight or more hours a day. Most of them, I think the average was probably around 12 hours per day. We've incorporated that into our counseling into the clinical population when patients are coming in and thinking about getting a cochlear implant for single-sided deafness. I think it's the same thing as what we're seeing with traditional cochlear implant patients, is that if you're wearing it less than eight hours, you're not going to get as big of a benefit as if you're wearing it more than eight hours. The folks that say, ÒOh, I'm just going to put it on when I'm going to a dinner or I'm just going to put it on when I'm sitting at work for a few hours.Ó We're not seeing the same jumps in improvement, especially early on as we are for those that are wearing it consistently every day. [0:39:57] DS: That makes sense. I guess you just have to Ð I mean, they're adults. They're a little more easy to reason with than the occasional kid, I guess. We can probably understand the logic of where it works. Just trust me on this. [0:40:09] MD: Yeah. At least, it excited me pretty often when I'm like, ÒWhat do you mean? Just tell them they have to wear it more.Ó She's like, ÒThey're five. That's not going to happen.Ó [0:40:18] DS: Oh, my gosh. Cool. I'd love to get into place-based mapping and how that's been a new way to approach this. You've taken it from how you get adequate loudness, how you get that equality and that fusion between ears. Now that we're learning more about the placement of the internal in the cochlea and how that can impact someone with SSD ability to adapt to, or accept the device, I guess, might be better wording, where did this idea of using place-based mapping originate and where is it heading and where are you at today with it? [0:40:53] MD: With the clinical trial, we selected the 31.5-millimeter electrode with the thought being that having this long array, the default frequency filters would better approximate cochlear tonotopicity. A few years ago, we had a resident who was completing his T32 research fellowship with us, Mike [inaudible 0:41:15]. He looked at a number of scans, post-operative CT scans, and used some technology to calculate the angular insertion depth of each of the electrode contacts across these individuals. What we found was first, the recipients of the 24, the 28, and then the 31.5-millimeter electrode array. Not surprisingly, the patients that had the shorter electrode array had more shallow angular insertion depths than the patients that had the longer electrode arrays. What was surprising was this wide variability in angular insertion depth for patients that had received the same electrode array. That opened our eyes to how the surgical approach, but also an individual's cochlear morphology contributes to where an electrode array ends up relative to cochlear tonotopicity. Even within our patients that received the 31.5 array, we did have these frequency to place mismatches between the frequency information that was being delivered by a given electrode and the cochlear place frequency. That got us thinking, well, would these patients do better if we use this information in the mapping? This is where I get really jazzed because it's just a whole new way of mapping, but not really. There were studies early on when cochlear implants were being developed and signal coding, strategies were being developed, thinking about this importance of matching the frequency information to the tonotopic place. The simulation studies showed that there was better speech recognition when you matched to cochlear place, as opposed to when you had these shifts, or these frequencies to place mismatches in the signal. On the patient side, we were just guessing. Because really, it was just linear insertion depth that we were thinking about. What is the length of the electrode array and then you estimate where that would end up. We didn't have this extra piece of imaging to see how the individual's cochlear morphology was influencing where the electrode array is ending up. We have that now. [0:43:25] DS: Yeah. I mean, what can we expect for a typical variation in that? I mean, we don't all have the same cochlea, regardless of congenital malformation of the cochlea. Those small millimeter differences can add up, right? [0:43:38] MD: Yeah. Something that, well see, in our study, and then as well as David Landsberger, who's up at NYU, just a similar study earlier, and saw that Ð I believe it was on average across cochlear implant recipients that there were electric frequency to place mismatches of 12 semitones, which is about an octave or is an octave, which is a huge amount. Really, the thought is, if you are within three semitones, that it's probably not that impactful of a mismatch. Once you get to half an octave, or six semitones, that really could be negatively impacting speech recognition with the device, at least acutely. That's the biggest argument is patients can listen to these mismatches and over time adjust to them, or acclimate to them. That may not always be complete. Not all patients may have the ability to do this. When we think about the SSD population, it might be really important to get that frequency information matched to a cochlear place, because we're thinking about this interaural match with the normal hearing ear. It might be, sure you can adjust on monaural hearing tasks. Yeah, your CNC word recognition is getting better. That's great with the implant alone. But when we put you in the sound field, and we're testing spatial hearing abilities, that we're not seeing those improvements that could be achieved if we were providing the frequency information that provided an interaural match with the normal hearing ear. [0:45:08] DS: That makes sense. I haven't gotten to experience this yet, but I feel like I can picture somebody who, especially if they've been already listening in a map that isn't accurately place-based. I don't know the best word, but their frequencies are off however many semitones and they've been listening with their normal hearing ear, hearing one way, and their implant, you're hearing this way. Then you finally get this shift where things are aligned properly. I feel like, that'd be a pretty quick improvement for them, right? It's not like this, you've got to you get some practice. I'm sure there's an element of that, too, it for those skills to arise. I feel like, it's like, oh, my gosh, this sounds normal. I mean, is that been the reaction that you've seen? [0:45:46] MD: Well, for long-term users, it's been interesting. First, one of the challenges we have is patients that have received a short electrode array and have single-side deafness is speaking specifically to that patient population. Some of them have rejected their implant because they never really acclimated to the sound quality. For those that have been open to this idea of switching, it takes a little bit of time to switch them back. We call this project filter switch because I just think that sounds fun. We have them, if you think about it, they've started to adjust to their default filters and what that sounds like. Then, depending on how much of a change, how much of a switch we're having to do, it might be that it takes them a little time to get used to it. Now some of them, as you said, right out the gate, say, ÒOh, this sounds so much better.Ó We had somebody recently who came in and we spent about three hours with her doing a number of different tasks, doing the ESRT, doing some pitch ranking, experiments, and things like that. Then at the end, she received her place-based map and she said, it was the best her implant had ever sounded. She had one of these shorter electrode arrays and was just overwhelmed with the sound quality change. I really think there is something to providing this match in the frequency information to support better sound quality, but also, better binaural hearing abilities. [0:47:07] DS: That's awesome. Getting that, though, so like you mentioned for a while, it was hoping that based on the length of the internal and the typical cochlear anatomy that this is about where things would line up. I know, typically post-implant, I don't even know if you would consider this imaging, but an X-ray is normally done to confirm placement, that everything's where it's supposed to be. Make sure there's no extra cochlear electrodes. Are CTs more commonly used post-implant to confirm that? It sounds like the CT is an important part of this. How has that information either been a setback or something you're looking forward to changing in the future? [0:47:41] MD: Yeah. At our center for adults, the postoperative CT is the standard of care, and that's to confirm a number of things. But that allows us to have access to this postoperative CT scan to do these place-based maps. Having the CT scan, you can see more of the structures, and so you're more confident in your cochlear morphology. We also, as you know, all of our patients, pediatric and adult, have the interoperative X-ray. We do have a script that we can use where, depending on the orientation of the head during surgery, which now all of our surgeons are on board with turning the head a certain degree so that we can get this beautiful cochlear view of the implanted ear so that we can look and identify some of these landmarks and are able to calculate angular insertion depth in those cases as well. I need to look a little bit more closely to see if we have both, how accurate are we between the two. But that has allowed us to also do place-based mapping in some children when we have this beautiful interoperative X-ray that we can use, too. [0:48:47] DS: I know with kids, it's tricky. There's the bits of radiation and things like that, right? [0:48:52] MD: Yes, yes. [0:48:53] DS: I do think this information is going to be so critical as we continue to evolve and how we approach mapping. Yeah, I'm excited to see what the future looks like for that. Actually, that's my next question. What does the future look like for this? I'm assuming, this isn't a very widespread tool yet. I know MED-L has a tool that they've rolled out for this specific purpose, and this might not be something you're privy to yet, but is this something that more centers are getting onboard with, or what do you see the future going for this process? [0:49:20] MD: Yeah. I think mapping this patient population overall is the next step, right? If we go back to EAS, it's funny how things swing between surgical and audiology. With electric acoustic stimulation, it was, can you preserve hearing? Oh, yay, they can. This is amazing. Then it swung back over to audiology of, okay, well, how do you program these devices to optimize it? With single-side deafness, I think that's where we are is, yay, this surgical procedure and the cochlear implant used postoperatively is benefiting this patient population. Now we have to figure out what is it that we're doing that helps to optimize that, and how can we make it better for more patients and more consistent across patients? I think, determining how to appropriately set the MCL is going to be that area. But then, this whole idea of matching the frequency information, so this place-based mapping procedure is something that's up and coming. For us, it's time-intensive right now, so how do you make that clinically feasible? Because right now, I review every scan. It takes me about 15 minutes to do that, and then I come up with the filter frequencies and send those to the clinical audiologists that they have it for mapping. That's having access to a CT scan and a good CT scan. Those things are really important in making that work, and how can we streamline that process that's going to be important for the next couple of years to figure out? [0:50:48] DS: Yeah. It sounds like, there's a lot of room to grow there, but I'm really excited to hear what comes of it. I know one of the things that's come out of y'all reviewing older scans, itÕs impacted patients I've seen, is you've found things tip fold over and things that previously hadn't been identified. Could you speak a little bit to some of the things you've learned in just reviewing previous scans for these kinds of things? [0:51:09] MD: Just to take it one step back, so one of the greatest things that I'm glad I did during the Ph.D. was I completed a course with Kevin Brown, who's one of our neurotologists on imaging and cochlear implantation. He had me participate in the temporal bone course that our residents take. It gave me a real appreciation for the skill set that is needed for this procedure, but then also, just thinking about the anatomy and how important it is with mapping and what we can learn from these different image modalities. I spent a lot of time with him looking at different CT scans, looking at X-rays, MRIs. With our clinical patients, there have been some where, now that we're seeing that place-based mapping could be something that's beneficial, where it's a ÒHey, could you take a look at this patient? They're not doing really well.Ó We'll pull up this X-ray from 15 years ago and see however many channels are extra cochlear, or that there was tip fold over some of these things that we were not expecting to find. Because really at that point it was, are you within the cochlea when you were using these images? Now, we can take a look at them and be more critical of them and say, well, how can we use this in mapping? Catching tip fold-overs, catching extra cochlear contacts, looking at serial images to see, has something backed out? That's also been really beneficial. We're seeing more and more how imaging should be part of our practice, because it's helping us identify some of these things right out the gate that could benefit the patient with mapping. For instance, if you see the tip fold-over identifying which contacts should be deactivated so that you're not stimulating the same site with multiple contacts. [0:52:53] DS: Those are awesome insights. I don't know that it was an intended outcome of looking at these, but I think it's so helpful and a really interesting way that we can start to utilize this information to shape maps, not just for people who are newly implanted, or just only with SSD, but all of these previous patients as we can utilize imaging more. I mean, do you see this being the future of mapping is more and more imaging being a part of the audiological process for that? I know, like you said, there's so many factors that go into that is having a good image to go off of and the technology that goes with it. Does this seem like where things are heading to you? [0:53:29] MD: The results that we're seeing with place-based mapping are so promising that my answer would be yes. If we think about where we are right now, we are using the post-operative image. There are groups that are using the pre-operative image in electrode array selection because you see this wide variability in cochlear duct length. Well, if your aim is to provide full cochlear coverage with your cochlear implant, and then you may want to measure the cochlear duct length and pick the length electrode that would better approximate those default filters with cochlear place. There are some groups that are exploring that as well, and you could see how that would build into hearing preservation candidates. If you know that they have a certain amount of acoustic hearing, how close do you want to get to that functional acoustic hearing region? Something, just as a tidbit of something that's coming that we have seen, as we've been looking more and more at these images, is we have seen a high incidence of electrode contacts within the functional acoustic hearing region for our hearing preservation and EAS users, which is just crazy to think about one, that you've got contacts that are within this functional acoustic hearing region, and the hearing is still functional over time. Then two, how should we be using that in mapping? Because it could be that that electric stimulation is masking the benefits of that low-frequency acoustic hearing. We've been exploring deactivating those contacts, turning the stimulation levels down below detection, things like that, to provide this equal access of the low-frequency acoustic cues and the electric stimulation. There are multiple ways that we could be using imaging in the way that we're programming. [0:55:10] DS: That's really cool. I'm excited to see that and how we have to approach that differently because I can definitely see how that interaction could be a bad thing. The things we haven't even considered yet, how we can Ð I'm just so excited for what the future looks like with imaging and cochlear implant mapping. I think it's a really cool step forward to getting more and more personalized for each patient. I definitely see it as the future. I'm excited for maybe more low-radiation options for our littles. I don't know what that looks like yet, but hopefully, we can get something in the near future so we can start utilizing this more. Cool. We're just about at the end of our time. I'm just curious. I like to have a lot of guests just end with, you've got an audience of a lot of students, seasoned clinicians. It's a really diverse audience of clinicians, researchers, there are a lot of SLPs who listen. If you just have not necessarily a life lesson, but a clinical thing, or a research thing, just a piece of information, or guidance, or whatever you'd like to share with people listening, what would it be? [0:56:06] MD: I'd say, our field is so exciting, because there's a lot that we know, but there's so much that we don't know. Every time we answer a question, five more pop up. I think that's what's so exciting about the cochlear implant field is this is an amazing technology that is benefiting so many patients. We're still learning, one, about who can benefit from a cochlear implant. But two, how can we program these devices to help them achieve their individual best outcomes? There's a lot that the brain can do with these signals. Some of these seemingly minor changes to a map can have a big impact on a patient's outcome. I think that's what gets me excited about the work that we're doing and is super promising for the field in moving forward. There's a lot that audiologists can do to improve the outcomes that patients have. Yeah. I think my advice would be, keep asking questions, keep experimenting, keep seeing what could work and what could benefit. Especially for those of us that work with cochlear implants, we know that option A that works with your first patient is not going to work with the second patient. You've always got to keep trying. [0:57:19] DS: That's awesome. That's great advice. I'm so grateful that you came on to talk about this really exciting new world of cochlear implant care. We're out of time. It's been a blast. But if people had more questions for you or anything like that, what would be the best way to get in touch? [0:57:35] MD: My email, mdillon@med.unc.edu is a great way. We also post a lot about our publications and experiences in the lab on our social media. Our CI research accounts on Twitter and Facebook will have those updates as well. [0:57:53] DS: Yeah, that's awesome. I'm sure people will be getting to you with all of their questions. I feel like, that is the blessing and the curse of being on this podcast. Previous guests are like, ÒIt was so great being on. I've gotten a lot of questions, but also met a lot of people. It's been cool.Ó Sorry for your inbox. [0:58:08] MD: Mapping is my favorite. Could talk about it all day. [0:58:11] DS: Awesome. Well, thank you again for coming on. It's been a blast and I hope you have a good rest of your day. [0:58:16] MD: Yeah. Thanks so much. [END OF INTERVIEW] [0:58:19] DS: That's all for today. Thank you so much for listening, subscribing, and rating. This podcast is part of an audio course offered for continuing education through SpeechTherapyPD. Check out the website if you'd like to learn more about the CEU opportunities available for this episode, as well as archived episodes. Just head to SpeechTherapyPD.com/ear. ThatÕs SpeechTherapyPD.com/ear. [END] OTE 40 Transcript ©Ê2023 On the Ear 1